Data Transformation Engine Intelligent Business Integration Reference Guide

Intelligent Business Integration Reference Guide

Chapter 3 - Methods of Execution

The core execution engine in Mercator products is developed in ANSI C for

platform portability and high performance. However, there are a variety of

mechanisms that can be used to invoke integration components, including a Java

API that enables Java-based interfaces to maps. Other Java-based mechanisms for

map execution are servlets and Enterprise JavaBeans (EJB).

The main methods for map execution are as follows:

♦ A Web-based execution model, where maps can be called and executed as a

synchronous transaction by a servlet running on a Web server and servlet

engine or an application server that has a servlet engine available. No

programming is required (Java or otherwise) in this execution model.

♦ An EJB execution model, where maps can be “wrapped” inside an EJB and

deployed to any EJB 1.0, EJB 1.1, or J2EE-compliant application server. Some

Java programming is required to be able to call the EJB-wrapped maps running

on the application server.

♦ Command-driven execution, primarily geared towards batch processing, using

the Mercator Command Server.

♦ Event-driven execution, where systems of maps can be coordinated together

by the Mercator Event Server to provide a scalable, distributed, multi-threaded

execution environment.

♦ An application embedded model, where maps can be embedded in third-party

applications using the Mercator Platform API, Mercator Programming Interface,

or the Java API.

Servlet Execution Model

Mercator offers a servlet-based execution model that enables a map to be invoked

by a Java servlet. This is particularly useful for Web browser-based interfaces

requiring a request and response mode of operation—the map is able to function

in a stateful fashion due to the servlet’s ability to maintain state on the HTTP

session. Using the Mercator’s Servlet Integrator, you can automatically generate

the necessary servlet code that will interact with the corresponding map. The

Servlet Integrator provides the ability to create browser-based request and

response interfaces without having to write any procedural code at all.